This 12 mm x 1.25 (1 5/16) Fine HSS Split Die is a hand and machine threading tool designed to cut or restore external ISO metric fine-pitch threads on rods, studs and shafts. Its primary use is to form M12 × 1.25 external threads where a finer pitch is required than the coarse M12 × 1.75 option, and the split design allows adjustment of thread engagement for accurate fit and easy release from the workpiece.

Manufactured from M2 high speed steel (HSS) and through-hardened, the die features ground cutting faces for consistent thread profile and a corrosion-resistant black oxide finish to reduce surface rust. The thread profile conforms to the ISO metric thread form and is compatible with ISO 261/965 and BS 3643 specifications; it is also consistent with the DIN 13 metric thread series. The die produces a standard ISO external thread (metric fine pitch), suitable for mating with standard nuts or tapped holes. The split configuration permits slight tightening or easing of the cut by compressing or separating the die in a standard round die stock (outer diameter approximately 1 5/16" to suit common stocks).

Use this die in general engineering, automotive repair, agricultural machinery maintenance, plant and equipment refurbishment, and fabrication shops where controlled fine-pitch threads are required. It can be used for hand threading with a die stock or in low-speed machine applications when securely clamped and properly lubricated. The HSS material offers good hot hardness and toughness, allowing re-sharpening when worn and reliable performance when cutting mild steel, alloy steel and stainless steels (with appropriate cutting fluid).

Key benefits include precise metric fine-pitch thread form, the adjustability of the split die for achieving the desired fit and clearing minor damage, material strength and re-sharpenability of M2 HSS, and the protective black oxide finish for extended tool life. The die is compatible with standard M12 threaded components manufactured to ISO/BS/DIN metric standards.

Duchy Fasteners stocks a broad range of taps and dies in metric and imperial sizes, available as individual dies and in sets, and supplied in various pack quantities to suit workshop and production requirements. Contact us for specific size availability and pack options.